In general, antimicrobial chemicals have been used for years to preserve plastics and textile materials. Furthermore, the prior art teaches the use of antimicrobials in pulp and paper manufacture. In some instances, the antimicrobial chemicals are applied as slime control agents and in the paper production. However, these slime control agents are normally extracted during the paper manufacturing process and are not considered to be of any value in protecting the finished paper.
The production of antimicrobial paper has most often accomplished by producing the desired paper in sheet form and coating the sheet with an antimicrobial coating in order to inhibit growth of fungi and bacteria thereon. For example, U.S. Pat. No. 2,833,669 is directed to a cellulosic product, the type used for medical, industrial, hygienic, and other similar purposes. This patent discloses the use of a bactericidal coating having a particular affinity for fiber substances. In particular, the patent teaches spreading the bactericidal coating across the paper product just before the fibrous web has been subjected to a drying process as part of the overall paper manufacture. The patent further discloses that the bactericidal layer may be applied to one or both sides of the web. The problem inherent in this type of process is the fact that the bactericidal coating may be easily rubbed off or otherwise destroyed, for example, during storage or shipping. Once the coating has been destroyed, there is no further antimicrobial or anti-bacterial material along the paper product for inhibiting micro-organism growth.
U.S. Pat. No. 4,533,435 teaches incorporating an antimicrobial additive into the binding agent of a heavy duty paper product. The antimicrobial additive thus migrates from within the binding agent onto the paper fibers in order to significantly eliminate the growth of micro-organisms thereon. Particularly, the antimicrobial additive described in U.S. Pat. No. 4,533,435 is chosen to be compatible with the binder material such that it resides in a colloidal suspension within the amorphous zones of the polymeric material which makes up the binder rather than being cross-linked with the polymeric material. Nonetheless, despite the improvements provided by this patent, the teaching of this patent is less than desirable because a substantial amount of antimicrobial chemical must be used in order for a sufficient amount of antimicrobial to be present along the surface of the paper.
Another problem with respect to prior art antimicrobial paper products is that it is necessary to incorporate large quantities of antimicrobial chemicals into the pulp. As a result, the paper manufacturing process becomes significantly uneconomical. In addition, if the antimicrobial chemicals are introduced at the wet end of the paper making process, they may be introduced into the waterway stream and thus contaminate rivers or water sheds, lakes, streams and even cause damage to wildlife as well as plant life. Thus, additional water treatment facilities may be necessary in order to neutralize the chemicals, thereby increasing the cost in the manufacturing process.